why is emulator talk not allowed here?

Makes no sense to me, explain mods

Because they're illegal. Well, the emulators themselves aren't, but ROMS are, thus it's not allowed here.

Because GS still thinks it's 2005.

except emulators and roms are not illegal at all + the main gaming forum, gaff, even allows talk of emulators but gamespot doesnt, just makes no sense

Downloading ROMs is technically illegal and often considered as piracy due to being unauthorised copies of copyrighted material. Ethically it's a bit of a grey area, but to say the least links or instructions for illegal content is disallowed as a legal precaution for the site.

You're probably safe with much older games, if only because they're no longer made or distributed so the company no longer makes anything from them anyway, and an argument can easily be made for ROMs of games you already own as well, but ultimately it's a legality issue whenever it comes to the ROMs used in emulators and much like everything else that is illegal it's not allowed on GS.

Nope, they are

Amiga Forever is perfectly legal. It's being sold openly and comes with a number of games and apps. However, other emulators, I'm not sure.

but why is emulator talk not allowed though? roms are grey area ok but emulator talk should be allowed

Amiga Forever is a licensed example so there's no copyright/piracy issues, the same sort of thing applies to a variety of sega game collection packs for megadrive/genesis games and sonic game series collections. In Amiga Forever's case the provided ROMs are licensed with the package and any ROMs obtained via the floppy disk conversion (of a floppy disk you own, provided you retain the floppy disk) are also legal. Emulator discussion is rarely about the entirely legal ones however.

Generally speaking there are no legal ROMs for emulation of the last 2 console generations due to overlap in activity, and beyond those accessible via the Wii virtual machine and equivalent emulation of PS1/PS2 games on the PS3 as well as any emulation that the Xbox consoles may allow the 2 generations before that also don't have legal ROMs for emulation at this point in time to my knowledge. Ultimately for unauthorised ROMs of older games it comes down to whether or not the publishers/creators want to press charges, in most cases they won't as it doesn't hurt their bottom line once they're no longer profiting from a product. However when a legal emulation of it is available they often are profiting from an old product. Though regardless any unauthorised copy is illegal.

Taking Amiga Forever as an example - an emulation discussion based around that is legal and would be allowed provided the discussion remains fully within legal restrictions (i.e. no download links for or instructions on finding unauthorised ROMs). The same applies to emulator discussion in general, but more often than not does it stray into technically illegal realms and moderators may sometimes lock a thread if they think it's heading in that direction.

Wine is similar (though not strictly an emulator, they'd probably be legal issues with reverse engineering code if it was too) in that it has many legal uses, but also illegal ones, which largely comes down to what's in the EULA's and the like.

It's worth noting that legality has little to do with the age of the product here - while legal emulation is more likely to be available for older products, the blanket rule is very much that emulating a specific game is illegal unless it is an authorised/licensed copy of said game. While companies are unlikely to press charges for a game that they no longer profit from, it is still illegal if it's an unauthorised copy.

Long story short: You can talk about emulation, but only if you stay within legal grounds. As this is rarely the case here, most emulation-related discussions end up being closed for legality reasons.